Field of the Invention
The present invention relates to a touch system, a touch panel, and a display device.
Description of the Related Art
With the development of information society, various types of requirements for a display device for displaying an image are increasing and, recently, various display devices, such as a Liquid Crystal Display (LCD), a Plasma Display Panel (PDP), and an Organic Light Emitting Diode Display Device (OLED), are being used.
Recently, a growing number of such display devices have moved away from related art input schemes using buttons, keyboards, mouses, etc. towards touch-based input schemes, which enable users to input information or commands intuitively and conveniently.
To provide such a touch-based scheme, a display device requires a touch system capable of accurately detecting the coordinate of a point touched by the user.
Related art touch systems employ a number of touch schemes, such as a resistive scheme, a capacitive scheme, an electromagnetic induction scheme, an infrared scheme, an ultrasonic scheme, etc., the capacitive scheme being most widely employed.
According to a related art capacitive touch scheme, two kinds of electrodes are arranged on a touch panel in different directions, driving signals are successively applied to electrodes arranged in one direction, sensing signals are sensed from electrodes arranged in the other direction, and touch coordinates are detected based on the sensed sensing signals.
However, accurate detection of touch coordinates requires, according to the related art capacitive touch scheme, that good sensing signals having strong resistance to noise be obtained.
Therefore, touch systems employing the related art capacitive touch scheme apply high-voltage driving signals, in order to increase SNR (Signal to Noise Ratio), or repeat driving and sensing a number of times.
However, high-voltage driving to obtain high SNR increases power consumption. Such an increase in power consumption resulting from high-voltage driving worsens in the case of touch panels having a large area, and may even pose serious problems to display devices, power consumption of which is a sensitive issue, such as mobile terminals.
Furthermore, an increased number of repeated driving and sensing for the purpose of obtaining high SNR has a problem in that too much time is taken before actually calculating touch coordinates, i.e. the report rate is low, so that detection of touch coordinates takes a long time.